1. Field of the Invention
This invention relates generally to the field of reconfigurable manufacturing tooling systems and more particularly to a flexible rail system for automatic positioning drill or tool systems which is unlimited in extension length and remains flexible over interlocking extensions.
2. Description of the Related Art
The use of automated positioning tooling systems for fabrication of large structural elements on aircraft and other large systems is prevalent in current manufacturing practice. However, precision flexible rail systems for tool positioning are difficult to make and handle in long lengths. To solve this problem rails are made in short lengths of 4 to 7 feet. To achieve a long rail the rails are simply spliced together. However, technical challenges arise in the splice. A typical splice tends to be crooked at the joint. While match drilling can make a straight joint, the end result is a non-interchangeable rail set. Non interchangeability is highly undesirable and considered impractical in most manufacturing environments.
The key problem characteristics are the difficulty in making straight rail splices that are interchangeable and maintain the flex characteristics of a flexible rail
There are other methods that have attempted to hold the rail joint reasonable straight, flexible and interchangeable. Unfortunately they all fall short of that goal. Examples include short and long sandwiching plates that carry stresses across each joint. The stresses are induced by bending the flexible rail to conform to a working surface
Previous devices such as short metal sandwiching clips are too short in length to achieve interchangeability and repeatable accuracy at the same time. Long sandwiching plates can be accurate and interchangeable but add significant local stiffness to the flex-rail. This stiffness can cause significant flat spots when the rail is flexed to a work piece contour
An exemplary prior art system and the tools positioned thereby is disclosed in U.S. Pat. No. 6,843,328 entitled Flexible Track Drilling Machine, having a common assignee with the present invention.
It is therefore desirable to provide unlimited-length rails for use with automatic position locking manual drills or tool positioning machines for use on new aircraft and other large structural system development programs. It is also desirable to provide a joint for use with such rails that is straight and interchangeable.